* Downton Abbey (TV series, 2010-2015): He created, wrote, and produced the critically acclaimed historical drama series.
* Downton Abbey (film, 2019): He wrote and produced the feature film adaptation of the series.
* Downton Abbey: A New Era (film, 2022): He wrote and produced the sequel to the 2019 film.
Beyond Downton Abbey, he has also written:
* The Importance of Being Earnest (film, 2002): A modern adaptation of Oscar Wilde's play.
* Gosford Park (film, 2001): A screenplay for the critically acclaimed mystery film directed by Robert Altman.
* Separate Lies (film, 2005): He adapted the stage play for the film.
* The Tourist (film, 2010): A romantic thriller he co-wrote.
* The English Patient (film, 1996): He contributed to the screenplay.
He has also written plays and other works.